A device for retaining and removing filaments of plastic material, or angel's hairs, from a flow of plastic material in form of granules, powders or flakes is disclosed. The device includes a main body defining a through channel through which the plastic material flows, a plurality of retractable elements carried by the main body and are movable between a retracted position, in which they leave the through channel unobstructed, and an extracted position, in which they protrude into the through channel for trapping the angel's hairs flowing together with the flow of plastic material along the through channel, and an actuating system for moving each retractable element between the retracted and extracted positions.